Meta-analysis of Fluid and Electrolyte Balance

Electrolyte and Fluid Balance Empirical Findings and Results

Considering the four prospective and retrospective studies analyzed, individual results relating to the types of replacement fluids used on various patients differed. A study that evaluated the use of colloids on multiple surgery patients in their postoperative phase indicated that natural colloids employed in intravenous fluids include blood products such as albumin solution and frozen plasma. In the results of the study, those postoperative patients who exemplified low albumin levels had colloids administered as the replacement fluid since they are beneficial for patients with low albumin due to the fact that they have low risks for adverse reactions.

While various previous studies explored the use of colloids and crystalloids as the primary replacement fluids in postoperative patients, the research that examined the use of human blood as a postoperative replacement fluid came up with results which highlighted both the advantages and disadvantages of the use of blood transfusion as a fluid replacement strategy. This study made an evaluation of the benefits and limitations of using blood as a replacement fluid for the use of 76 patients as participants and compared their immune system before and after the surgery and the blood transfusion. According to the results, the overall postoperative infection rate which was as a result of the use of human blood as a postoperative replacement fluid was at 28% and 4.6% for those patients who did not get any blood transfusion in their postoperative phase.[1] Regarding immunological tests done, the results of this study did not show any significance difference between the transfused and un-transfused patients groups, after the surgery had been done. Nevertheless, a comparison is done on the pre- and postoperative patients’ data, indicated an impairment of natural killer (NK) in all patients regardless of their postoperative blood transfusion status. Additionally, those patients who did not get any blood transfused indicated a significant synthesis of the interferon-gamma and iterleukin-2 (Quintiliani et al., 1997).[2] Therefore, the results showed that, when blood is used as a replacement fluid, there is a possibility of the blood transfused to induce immunosuppressive effects the postoperative patient. This, in turn, increases the patient’s susceptibility to various infections during their postoperative phase.

On the other hand, several other studies done sought to determine the benefits of the use of blood as a replacement fluid when blood transfusion is administered to the postoperative patient. The result of a study that made use of 8787 hip fracture postoperative patients at the age of 60 and above, indicated that blood transfusion on postoperative patients who had high haemoglobin levels of about 80 g/l and above did not seem to influence the risk of postoperative mortality in the elderly patients, who were used as participants in this particular study. However, patients who had hemoglobin levels that were less than 80g/L are the patients who required blood transfusion in their postoperative phase. These results, however, were in preclusion of additional analysis of the relation between transfusion and mortality.

Fluid Replacement for Blood Loss

i.    Blood transfusion is the most physiological way to replace any blood lost during and after surgery.

ii.    One of the greatest advantages of blood transfusion is that it is the only approved type of fluid replacement method that is capable of carrying oxygen; this is because a majority of the blood substitutes that are intended to carry oxygen are usually underdeveloped.

iii.    In postoperative fluid replacement, blood transfusion corrects any hypotension that is secondary to blood loss.

iv.    It is a fluid replacement strategy that is more effective than the crystalloids and a lot cheaper than the colloids when it comes to correcting hypotension.[3]

Additionally, other retrospective studies analyzed highlighted the advantages of using colloids over crystalloids. According to the findings of the study, colloids were characterized as fluids that can be effectively used in the postoperative phase especially for critically ill patients since they may consist of synthetic molecules which cannot distribute across vascular barriers. This is because these synthetic molecules that characterize the colloids are much larger than those electrolyte components in the crystalloid solutions. As a result, the colloids are characterized by the fact that they tend to provide less free water, as compared to the crystalloids and for this reason, they primarily stay in the intravascular space.[4]

Some typical examples of these large synthetic molecules are; dextrans, gelatins and hydroxyethyl starch (HES). Usually, in the postoperative procedure, colloid solutions, which in the event of by dissolving colloid molecules in isotonic saline solutions, are most commonly used in the body fluid resuscitation. One of the reasons why colloids are used in the postoperative fluid replacement procedure is because they are crucial for increasing the body’s osmotic pressure as well as increasing the intravascular volume.[5] When compared to the crystalloids, colloids are the most preferred postoperative replacement fluids since they require less volume to produce the desired effects. Different studies examining the relevance and importance of resuscitation postoperative fluids have continually highlighted that various types of colloids such as Albumin are mostly used for fluid replacement in Severe Sepsis (ALBIOS) postoperative patients. In this regard, different crystalloid and colloid products have both their advantages and disadvantages when used in postoperative intravenous replacement fluids.

Conclusion and Discussion


Crystalloid vs Colloid

While a majority of previous studies done cited colloids and crystalloids as the primary components of replacement fluids used on postoperative patients, there seemed to be a significant agreement on the discussions done by different scholars, on the type of replacement fluid that is beneficial than the other. However, from a broader perspective, fluid replacement and fluid resuscitation in postoperative patients are directly related to the replacement of the standard blood volume with intravenous (IV) fluids which are intended to maintain the patient’s adequate organ perfusion that also ensures healthy body metabolic processes.[6] Usually, the types of intravenous fluids that are primarily used in postoperative fluid replacement are those fluids that are within the group of volume expanders. Therefore, in most cases, fluid replacement in postoperative patients is provided either in the form of colloids and crystalloids. When used as replacement fluids, each type of fluid has its advantages and disadvantages, based on the patient’s disease state or cell enzyme composition.

On the other hand, when these two common types of replacement fluids are used as plasma volume expanders, colloids, crystalloids or a mixture of the two are mostly used in fluid replacement in patients suffering postoperative hypovolaemia. In the same vein, physiologic saline solutions which are characterized by a 0.9% Sodium chloride solution are used in postoperative fluid replacements. This is due to the fact that they are isotonic and for this reason, they are highly preferred on ailing, postoperative patients because they do not cause the potentially dangerous fluid shifts. [7]

Age Relation to Fluid Replacement for Blood Loss

According to some studies analyzed, changes in body fluid, water, and electrolyte content in the body tissues in the postoperative phase may be as a result of various factors. The age of the patient, to be precise, determines the type of replacement fluid that can be applied on different postoperative patients, at different times.[8] Several analyzed studies that made use of content analysis as the primary method of the study concluded that elderly postoperative patients are more susceptible to dehydration and electrolyte abnormalities, as compared to younger patients. These results were highly attributed to by factors such as physical body weakness which restricts access to fluid intake and also the loss of more fluids during surgery as compared to younger patients. Besides, older patients are more prone to physiological stress, as a result of the surgical process. This, in essence, causes them to be more predisposed to water retention and electrolyte abnormalities. This being said, previous studies done have increasingly indicated that positive fluid balance is an independent risk factor for both mortality and morbidity in postoperative critically ill patients.[9] Colloids and crystalloid solutions are therefore used to rectify this condition since it is due to the age-related pathophysiological changes that are related to age, that affect the handling of fluids and electrolytes in older postoperative patients. For this reason, the analyzed studies consider elderly patients undergoing the postoperative phase as a high-risk group, requiring special attention during the postoperative therapy.